Answer: 1.58 x [tex]10^{23}[/tex]
Explanation:
1 mole of magnesium chloride has a mass of 95.211 g and contains 6.022⋅[tex]10^{23}[/tex]formula units of magnesium chloride, you can say that,
25.0 g x (6.022 x [tex]10^{23}[/tex] form units MgCl2) /95.211 = 1.58 x [tex]10^{23}[/tex]
